What causes diabetes mellitus?
Insufficient production of insulin (either absolutely or relative to the body's needs), production of defective insulin (which is uncommon), or the inability of cells to use insulin leads to hyperglycemia and diabetes mellitus. This latter condition affects mostly the cells of muscle and fat tissues, and results in a condition known as "insulin resistance." This is the primary problem in type 2 diabetes. The absolute lack of insulin, usually secondary to a destructive process in the pancreas, is the particular disorder in type 1 diabetes.
In Type I diabetes, the body's defense system (known as the immune system) destroys cells (beta cells) in the pancreas that form and release insulin. The destruction of the cells that form and release insulin is probably due to the body's response in fighting against a virus infection. In other words, the body responds to the virus by attacking the cells that make insulin. As a result, little or no insulin is produced or released, and there is not enough of it in the body. In some cases, the destruction of the insulin producing cells is caused by inflammation of the pancreas (a long organ in the back of the belly).
Diabetes mellitus also tends to run in families. This means that the child of a parent with diabetes has a higher chance of developing the same type of diabetes than a child whose parents do not have diabetes. However, only a small percent of people who inherit the genes for Type I diabetes (insulin-dependent) actually go on to develop the disease. Genes are units of material contained in a person's cells that contain coded instructions as for how certain bodily characteristics (such as eye color) will develop. All of a person's genes come from his/her parents. So why do some people who inherit the genes for Type I diabetes go on to develop the disease while others do not? The answer is that in many cases (but not all), Type I diabetes may occur because of having the genes for this disease as well as having a delayed reaction to a virus that damaged the pancreas several years earlier.
There is a subgroup of people with Type I diabetes in which the cause is not known. This is known as idiopathic diabetes. In these individuals, the need to take insulin injections can very from time to time. In other words, sometimes it will be necessary for them to take the insulin injections and other times it will not. Unlike Type I diabetes, a greater percentage of people who inherit the genes for Type II diabetes (non-insulin-dependent) actually go on to develop the disease. Thus, there appears to be a strong genetic component to Type II diabetes. However, it is generally overweight people who go on to develop this form of diabetes. Obese (very overweight) people are particularly likely to develop the Type II form, rather than the Type I form. Such people tend to have very large bellies.
In societies where people are making a lot of money, there are more and more cases of Type II diabetes mellitus. Why? The people living in such societies have more money and can buy more food. This means that these people eat more, which leads to an increase in the number of overweight people and thus, an increase in the amount of people with Type II diabetes mellitus. People with Type II diabetes also tend to have high amounts of fat and fatty proteins in their blood. Having a lifestyle in which one does not exercise much and sits around most of the day is another risk factor for developing diabetes. Another risk factor is having a diet that is high in fat a low in dietary fiber. Dietary fiber is a term for chemical substances in the cells of plants that cannot be digested by the human body.
Other factors that can increase the chance of developing diabetes mellitus include: pregnancy, high blood pressure, infections, and certain illnesses. Illnesses that can cause diabetes mellitus include pancreatitis (inflammation of the pancreas) and thyrotoxicosis (a poisonous condition that results from an overactive thyroid gland). The thyroid gland is a butterfly-shaped organ located in front of the neck that produces a natural chemical known as hormones that affect virtually every cell in the body and many functions such as heart rate, energy level, and skin condition.
Certain drugs can also lead to diabetes mellitus, such as diurectics, which increase the amount of water flowing into the urine (pee). Benzothiazides (also known as thiazides), which are drugs that reduce high blood pressure and increase the amount of water flowing into the urine, can also lead to diabetes mellitus. Corticosteroids can also lead to diabetes because they work against the actions of insulin. Corticosteroids are a group of drugs that act similarly to a natural chemical in the body known as corticosteroid hormone. Corticosteroid hormones control the body's use of nutrients and the amount of water and salts in the urine (pee). Even excess levels of natural corticosteroid hormones can cause Type II diabetes mellitus. Diabetes caused by corticosteroids is sometimes known as steroid diabetes.
Hormone treatments, such as human growth hormone, thyroid hormone, and adrenocorticotropin hormone (ACTH) can lead to diabetes mellitus. Hormones are natural chemical produced by the body and released into the blood that have a specific effect on tissues in the body. Growth hormone promote growth, ACTH promotes the release of corticosteroids (see last paragraph), and thyroid hormone helps with metabolism. Metabolism is the chemical actions in cells that release energy from nutrients or use energy to create other substances. Sometimes hormones are administered as medical treatment for certain medical conditions. For example, ACTH is used to treat allergies that won't go away, various skin disorders, and other problems.
More information on diabetes mellitus
What is diabetes mellitus? - Diabetes mellitus is a a condition characterized by hyperglycemia resulting from the body's inability to use blood glucose for energy. Diabetes mellitus can result in coma. Over time, complications can include nerve injury, blindness, kidney failure, and premature atherosclerosis with all of its complications.
What causes diabetes mellitus? - Diabetes mellitus is a disorder caused by insufficient production of the hormone insulin by the pancreas, or insensitivity of cells to the effects of insulin. Insulin is responsible for the absorption of glucose into cells for their energy needs and into the liver and fat cells for storage.
What is insulin? - Insulin is a hormone that is produced by specialized cells (beta cells) of the pancreas. In addition to helping glucose enter the cells, insulin is also important in tightly regulating the level of glucose in the blood.
What types of diabetes mellitus are there? - There are four main types of diabetes mellitus. They are type 1 diabetes mellitus, type 2 diabetes mellitus, type 3, and Gestational diabetes mellitus (type 4).
What is type 1 diabetes? - Formerly known as juvenile diabetes or insulin-dependent diabetes, type 1 diabetes is a life-long condition in which the pancreas stops making insulin. Type 1 diabetes develops most often in young people but can appear in adults.
What is type 2 diabetes? - Type 2 diabetes is the most common form of diabetes mellitus. People with type 2 diabetes produce insulin, but either do not make enough insulin or their bodies do not use the insulin they make. Type 2, also known as non-insulin dependent diabetes, typically occurs after the age of 40 years.
What're signs and symptoms of diabetes mellitus? - Type 2 diabetes almost always has a slow onset (often years). Early symptoms of Type 1 diabetes are often polyuria (frequent urination) and polydipsia (increased thirst, and consequent increased fluid intake).
What is diabetes insipidus? - Diabetes insipidus (DI) is a disease characterized by excretion of large amounts of severely diluted urine, which cannot be reduced when fluid intake is reduced.
What is diabetic coma? - Diabetic coma is a medical emergency in which a person with diabetes is unconscious because the blood glucose level is too low or too high. Patients with diabetes mellitus type 1 are especially prone to this condition.
What are the complications of diabetes mellitus? - Many people with diabetes mellitus eventually develop complications. A very common short-term complication of diabetes mellitus is hypoglycemia (abnormally low blood sugar levels).
How to diagnose diabetes mellitus? - The diagnosis of type 1 diabetes is usually prompted by recent symptoms of excessive urination (polyuria) and excessive thirst (polydipsia), often accompanied by weight loss. The diagnosis of other types of diabetes is made in many other ways.
Diagnosis protocol for diabetes - People over age 45 should be tested for diabetes. If the first blood glucose test is normal, they should be re-tested every three years. A diagnosis of diabetes is made when any three of these tests is positive, followed by a second positive test on a different day.
What is the treatment for diabetes? - Diabetes is a chronic disease with no cure, but it can almost always be managed effectively. Nowadays, the goal for diabetics is to avoid or minimize chronic diabetic complications, as well as to avoid acute problems of hyperglycemia or hypoglycemia.
What type of diabetes diet is suggested? - For some people with diabetes mellitus, a healthy diet and weight loss is enough to keep glucose levels in the blood normal.
What medications are available for diabetes? - Oral diabetes medicines, or oral hypoglycemics, can lower blood glucose in people who have diabetes, but are able to make some insulin. Six FDA-approved oral diabetes medications are now on the market.
How to prevent diabetes? - Diabetes prevention is proven, possible, and powerful. Studies show that people at high risk for type 2 diabetes can prevent or delay the onset of the disease by losing 5 to 7 percent of their body weight.
What should a child diabetes do every day? - To control diabetes and prevent complications, blood glucose levels must be as close to a "normal" range as safely possible. Families should work with a health care provider to help set a child's or teen's targets for blood glucose levels.
Smoking and diabetes - There is a growing body of evidence to suggest that smoking is an independent risk factor for diabetes and that among people with diabetes, smoking aggravates the risk of serious disease and premature death.